DEFERRED ASSERTIONS AND OTHER PIPELINE DATASETS - Managing Time in Relational Databases - page 264

November 2011 to an effective end date of 12/31/9999. Every
version in this episode is currently asserted.
We will now submit a deferred temporal update. Again, we
assume that it is now January 2013. That transaction looks like
this:

UPDATE Policy [P861,,, $55] May 2012, Jul 2012, Jan 2090

The three temporal parameters following the bracketed data
are the effective begin date, effective end date and assertion
begin date. All temporal updates discussed so far have accepted
the default value for the assertion begin date, that value being
Now(). Here, with our first deferred transaction, we override that
default with a future date.
There are several things to note about this transaction. First of
all, the object specified in this transaction is policy P861, and the
transaction's effective timespan is May 2012 to July 2012, i.e.
the two months of May and June 2012. The assertion begin date
is January 2090, a date which is several decades in the future.
The first thing the AVF does is to split one or more rows in the
Policy table into multiple rows such that one or a contiguous set
of those rows has the oid and the effective timespan specified on
the transaction. When a set of one or more contiguous asserted
version rows, and a temporal transaction, have the same oid
and also the same effective time period, we will say that they
match .
Since the transaction specifies an effective timespan of [May
2012 - July 2012], the AVF modifies the current assertions for
P861 so that one version matches the transaction. That is P861
(r6), as shown in Figure 12.3 .
This results in a set of rows that are semantically equivalent
to the original row, those rows being P861(r5, r6 & r7). They
cover the same effective time period as the original row; and
they contain the same business data as the original row. Note

Policy Table

copay

Row
#
1

oid eff-beg eff-end asr-beg asr-end epis-

beg

clinet type row-crt

P861
P861
P861
P861
P861
P861
P861

Nov11 Mar12 9999

9999

C882 HMO $20

$50
$30
$40
$30
$30
$30

Nov11
Mar12

Nov11 Nov11

2
<3>
4
<5>
<6>
<7>

Apr12 Mar12 C882

C882
C882
C882
C882
C882

Mar12 Nov11

Nov11
Nov11
Nov11
Nov11
Nov11

PPO

Apr12
Aug12

Apr12 Aug12 Apr12 Jan13 HMO

POS

9999 9999

9999
9999
9999

Aug12 Aug12

May12 Jan13 Jan13

Jan13
Jan13

Apr12 HMO

HMO
HMO

May12 Jul12 Jan13

Jan13

Jul12 Aug12

Figure 12.3 A Current Episode: Effective Time Alignment.